Ask your AI assistant any tax question and get answers backed by the Internal Revenue Code, Treasury Regulations, IRS Publications, Revenue Rulings, IRS Notices, state tax codes, and U.S. Tax Court opinions. No more hallucinated citations.
What are the requirements for the home office deduction?
Under §280A, a home office deduction requires the space to be used:
What about the simplified method?
Works inside the AI tools you already use
The Problem
Thomson Reuters Checkpoint and CCH IntelliConnect charge thousands per seat per year for clunky web portals. Meanwhile, your AI assistant has no access to authoritative tax sources. It guesses, hallucinates citations, and can't tell you where it found the answer.
Legacy platforms charge well into the thousands per seat per year. Small firms and solo practitioners get priced out of professional-grade research.
ChatGPT and Claude are great at reasoning about tax law, but without access to real authorities, they fabricate section numbers and cite regulations that don't exist.
Consumer tax tools use outdated information with no citations. When you're advising a client, you need authoritative, up-to-date sources you can verify.
The Proof
Without taxmcp.io, a leading AI model sounds authoritative on tax. It's right often enough that the wrong answers slip through into client work. We put the same stratified set of U.S. federal tax questions to it twice: once on its own, once connected to taxmcp.io, with every answer independently graded against primary authority. Same model, same questions; the only variable was access to the source.1
on recent-law questions1
a failing 4.8 without taxmcp.io
free of critical errors1
1 in 3 carried one without taxmcp.io
exact figures & dates correct1
vs 89.6% without taxmcp.io
overall accuracy grade1
up from 7.4 without taxmcp.io
Right or tied on 93% of questions1, and every answer grounded in the Internal Revenue Code, Treasury Regs, IRS Publications & rulings, with a verifiable link.
Three real benchmark questions, graded 0–10. Average lift across the full set: +2.43.
EBIT or EBITDA basis for the interest limitation after OBBBA?
“EBIT basis. The EBITDA add-back only applied before 2022.”
“EBITDA basis, permanent. OBBBA §70303(a) struck the 2022 cutoff.”
What is the 2026 Form 1099 reporting threshold?
“$1,000 for 2026,” then “corrected” itself to the same wrong number.
“$2,000, raised by OBBBA §70433(a).”
What bonus depreciation rate applies to equipment acquired in mid-2025?
“40% bonus for 2025. Pending legislation could restore 100%.”
“100%, permanent. OBBBA §70301; Notice 2026-11.”
1 Independent benchmark across a stratified set of U.S. federal tax questions (single run), each answered by the same leading AI model with and without taxmcp.io and graded against primary authority. Mean grader score 0–10; ranges are standard error across questions.
How It Works
Connect taxmcp.io to your AI assistant, then ask tax questions the way you normally would. Every answer comes back with real citations.
Add taxmcp.io to Claude Desktop, ChatGPT, or your preferred AI tool. One URL, under two minutes, and you're researching.
Ask tax questions in plain English. “What are the QBI deduction requirements?” “Show me §199A.” Your AI searches the actual IRC, regs, and rulings.
Every answer includes the exact section number, source URL, and cross-references. Real citations you can verify and share with clients.
Features
Pull the full text of any U.S. Tax Court opinion by citation or case name (49,000+ opinions back to 1942) and gauge how influential one is with a citation graph built from 500,000+ links between opinions.
Ask questions the way you think about them. “Can my client deduct home office expenses?” returns the exact IRC sections, regs, and rulings that answer it.
Every result cites the exact section number with a link back to the official government source. No hallucinated references. No ambiguity. Citations you can put in a memo.
See how sections connect. When you look up §199A, instantly find every regulation, ruling, and related code section that references it, and everything it references.
Internal Revenue Code, Treasury Regulations, 27 IRS Publications, IRS Notices from 2003–present, and Revenue Rulings from 2019–present, plus 49,000+ U.S. Tax Court opinions on Pro+. All searchable from one place.
Our system checks official government sources regularly for changes. You always get the latest version of the law, not last year's snapshot.
Connects to Claude Desktop, ChatGPT, and other AI tools. Your AI assistant gets real tax research capabilities built right in.
Who It's For
Research client positions faster with cited IRC sections, regs, and rulings, right inside your AI assistant.
Professional-grade tax research without the enterprise price tag. Free to start, scales with your practice.
Every answer links to authoritative government sources you can verify and cite in memos and opinions.
Pricing
Free for individual practitioners. Upgrade for unlimited federal research, or add Tax Court case law and state tax codes with Pro+.
Free
For individual CPAs, EAs, and tax professionals getting started with AI research.
Pro
Unlimited access to every federal tax source. For practitioners who need comprehensive research.
Pro+
For practices that need case law and multi-state coverage. Adds Tax Court opinions and state tax codes on top of everything in Pro.
State Coverage
State tax code research is included with Pro+. Multi-state coverage is rolling out continuously through 2026; the rest of the country is on the roadmap.
+ 26 more states rolling out through 2026
Need a state that’s not listed? Let us know →Connect taxmcp.io to your AI assistant and get answers backed by the actual tax code. Free to start, takes under two minutes.
FAQ
Yes, on the Pro+ plan. taxmcp.io indexes 49,000+ United States Tax Court opinions dating back to 1942, both regular (T.C.) and memorandum (T.C. Memo.) decisions. You can pull the full text of an opinion by citation or case name, then check its citation history against a graph of 500,000+ links between opinions to see how often it has been cited since. This reflects citation activity, not a Shepard’s-style validity check, so always confirm an opinion is still good law before relying on it.
taxmcp.io indexes five core federal tax source types: the full Internal Revenue Code (Title 26), Treasury Regulations, 27 IRS Publications, IRS Notices from 2003 to present, and Revenue Rulings from 2019 to present. The Pro+ plan adds 49,000+ United States Tax Court opinions (case law dating back to 1942) and state tax codes. All sources are searchable from a single query.
Legacy platforms like Thomson Reuters Checkpoint and CCH IntelliConnect charge thousands per seat per year for web portal access, and their AI layers like CoCounsel Tax sit on top of those subscriptions. taxmcp.io starts free, is $9/month for unlimited federal research, and $29/month with Tax Court case law and state tax codes included. It works inside the AI tools you already use (Claude, ChatGPT) and every result links directly to authoritative government sources.
Yes. taxmcp.io provides an MCP server that connects directly to Claude Desktop and ChatGPT. Install with a single command and your AI assistant gains access to real tax authorities. It also works with any other MCP-compatible client.
Not yet. We're focused on delivering the best MCP experience first. A REST API is on our roadmap. If you have a specific use case, reach out and we'll keep you posted.
Our system checks official government sources regularly for changes. You always get the latest version of the Internal Revenue Code, Treasury Regulations, and other authorities, not last year’s snapshot.
The free plan includes 20 searches per day with access to the Internal Revenue Code. It works with Claude Desktop and ChatGPT, and every result includes real citations. Upgrade to Pro ($9/month) for unlimited searches across all five federal source types, or Pro+ ($29/month) to add Tax Court case law and state tax codes.
From the Blog
On June 24, 2026, the IRS Office of Professional Responsibility told every tax professional that AI hallucinates and the liability is theirs. Here is what OPR Alert 2026-19 actually requires under Circular 230, when AI use crosses into malpractice, and the verification gap that makes 'just check the output' harder than it sounds.
A general-purpose model will hand you a Tax Court case that reads perfectly and never existed. Here is the mechanism behind the fabrication, the two failure modes unique to case law, and how to cite opinions you can actually open.
The honest answer is not yes or no: it is 'trust it for what.' AI does two jobs in one fluent paragraph, and only one of them is reliable. Here is where the line falls, why it falls there, and the three-question test that tells you when an AI tax answer is safe to rely on.
Most 'best AI tax tool' lists rank features. The only question that reorganizes the whole list is where the citations come from. Here is the 2026 landscape sorted by that line (general assistants, incumbent platforms, AI-native research, and the grounding layer) with a rubric for choosing.
ChatGPT will hand you a confident citation to a Code section that does not exist. Here is the mechanism behind the fabrication, why tax citations are uniquely exposed to it, and the four habits that catch it before it reaches a client.
A research memo is only as good as its weakest cite. Here is a division of labor that lets AI carry the drafting while primary authority carries the law, walked through a full §280A home-office memo you can copy.